Opuntia can play host to the cochineal, an insect that produces white patches that, when crushed, release a crimson dye called carmine. The dye traditionally was used to color textiles as well as to tint paint by early European masters.

Opuntia can play host to the cochineal, an insect that produces white patches that, when crushed, release a crimson dye called carmine. The dye traditionally was used to color textiles as well as to tint paint by early European masters. (Ann Summa)